class Test{
    val map = mapOf(
    	1 to "a",
        2 to "b"
    )
    fun Int.switch() = map[1] ?: "c"
}

fun main() {
    1.switch() ///???
    /////
}

with (test){ 1.switch() }

String.toDate()

toDate()

with (mapper){ int.toDate() }

CoroutineScope.foo()

mapper.doMap(1)

with